The Electromagnetic Spectrum

The Electromagnetic Spectrum:

  • Electromagnetic waves are oscillations of electric and magnetic fields, which travel through space carrying energy from one place to another.
  • They are classified as transverse waves and can travel through a vacuum at a speed of approximately 300,000 km/s, often referred to as the speed of light.
  • The electromagnetic spectrum encompasses all different types of electromagnetic waves, having various levels of frequency and wavelength.
  • High frequency waves have short wavelengths and high energy levels, while low frequency waves have long wavelengths and lower energy levels.
  • The spectrum can be divided from low to high frequency into: Radio Waves, Microwaves, Infrared, Visible Light, Ultraviolet, X-rays and Gamma Rays.
  • Radio Waves: These are used in broadcasting radio and television signals. They have the lowest energy, longest wavelengths and lowest frequencies of all electromagnetic waves.
  • Microwaves: Used for satellite communications, mobile phones, radars and cooking food. They have slightly higher energy, frequency, and shorter wavelengths than radio waves.
  • Infrared: This range is used for thermal imaging, remote controls and fibre optic communications. Infrared waves have greater energy, frequency, and shorter wavelength than microwaves.
  • Visible Light: This is the only part of the spectrum human eyes can detect and is used for sight, photography, and illumination.
  • Ultraviolet: These waves are used in tanning beds, sterilisation of medical tools and validation of bank notes. They have higher energy and frequency, and shorter wavelength than visible light.
  • X-rays: Utilised for medical imaging and security screening. They have even higher energy, frequency and shorter wavelength than ultraviolet waves.
  • Gamma Rays: Produced in nuclear reactions, they have the highest energy, highest frequency and shortest wavelength on the spectrum. They are used in cancer treatment, sterilisation of medical supplies and food.
  • Different wavelengths are absorbed, transmitted, and reflected by different surfaces in different ways. For example, black surfaces absorb all wavelengths and white surfaces reflect all wavelengths.
  • The ionising radiation portion of the spectrum (UV, X-rays, Gamma rays) can cause harm to living tissues and can be dangerous. Safety precautions must be taken when using these higher energy waves.